Not sure i agree with you there. Although it depends what you mean by 'overrated'. Oasis arent everyones cuppa, but they have written some phenomenaly catchy tunes and have inspired an awful lot of people to pick up guitars. Coldplay have also written some damn fine tunes despite their singer bein a bit daft. U2 seem to have lost their way over their last few albums, perhaps buying into and believing their own hype. Bono can be a powerful frontman if he keeps his political mouth closed. The Edge, too is certainly talented and a positive influence on a lot of guitarists, but he does talk w*nk.
Im not sure, though, who i would call overrated, but Kanye West would be high on the list. As would The Proclaimers (only famous coz of one song sung with a Scottish accent), and The Bee Gees.
Adam